The application Keyport is a platform that utilizes the Bitcoin Cash (BCH) network’s OP_Codes and allows users to send and accept encrypted messages built on top of the BCH chain and the Toku protocol. The new platform Keyport was created by Atlantislabs and it allows anyone to message each other in an encrypted fashion while communications are saved to the BCH chain in an OP_Return transaction and only the recipient can decrypt the messages.
https://news.bitcoin.com/newly-launched-keyport-platform-enables-bch-powered-encrypted-messaging/